Multiple dosing of ephedra-free dietary supplements: hemodynamic, electrocardiographic, and bacterial contamination effects.
Study Goal
The researchers aimed to evaluate the effects of ephedra-free dietary supplements containing caffeine on heart rate, blood pressure, and ECG parameters in healthy men.
Results Summary
The study found that caffeine-containing supplements significantly increased systolic and diastolic blood pressure, heart rate, and decreased bradycardia runs, while also causing frequent abnormal atrial/ventricular events and gastrointestinal/sympathomimetic symptoms. Two supplements were contaminated with Bacillus species, raising additional safety concerns.
Population
Twelve healthy men.
Effective Dosage
Not specified (supplements ingested three times daily).
Duration
3 days.
Interactions
None mentioned.
| Intervention | Direction | Endpoint | Population | Dosage | Impact | Claim # |
|---|---|---|---|---|---|---|
Four popular ephedra-free dietary supplements | increase | mean systolic blood pressure (SBP) | Twelve healthy men | 10.8 ± 2.5 mm Hg | showed significant increases | #1 |
Four popular ephedra-free dietary supplements | increase | mean diastolic blood pressure (DBP) | Twelve healthy men | 5.3 ± 3.1 mm Hg | showed significant increases | #2 |
All supplements | increase | heart rate (HR) | Twelve healthy men | - | significantly increased | #3 |
All supplements | decrease | bradycardia runs | Twelve healthy men | - | decreased | #4 |
All supplements | increase | abnormal atrial/ventricular events | Twelve healthy men | - | frequently noted | #5 |
Two supplements | increase | microbial load | - | with Bacillus species | were heavily contaminated | #6 |
Four popular ephedra-free dietary supplements were evaluated for their effects on heart rate (HR), blood pressure (BP), and electrocardiographic (ECG) parameters. Twelve healthy men participated in a study randomized for product sequence, with a 21-day washout period between supplement-administration phases. Throughout the study, Holter monitors were used to assess ECG and HR activity. BP was assessed automatically on multiple occasions. The supplements were ingested three times daily for 3 days. Caffeine content, microbial load, and serum caffeine concentrations were determined. Mean systolic (SBP) and diastolic BP (DBP) readings showed significant increases relative to baseline (10.8 ± 2.5 and 5.3 ± 3.1 mm Hg, respectively; P < 0.05). All supplements significantly increased HR and decreased bradycardia runs; abnormal atrial/ventricular events were frequently noted. Gastrointestinal and sympathomimetic symptoms were also common. Two supplements were heavily contaminated with Bacillus species. In light of these findings, the use of ephedra-free dietary supplements should be discouraged in individuals with hypertension, diabetes, or other cardiovascular diseases.